Which sentence is written correctly? Curtis learned firefighting skills when he sailed aboard the ‘USS Forrestal.’ Curtis learned firefighting skills when he

Which sentence is written correctly?

Curtis learned firefighting skills when he sailed aboard the ‘USS Forrestal.’
Curtis learned firefighting skills when he sailed aboard the USS Forrestal.
Curtis learned firefighting skills when he sailed aboard the “USS Forrestal.”
Curtis learned firefighting skills when he sailed aboard the USS Forrestal.